[clang-tools-extra] 4001ae1 - [clang-tidy] readability-container-size-empty - detect missing usage of .empty() on string_literals

Piotr Zegar via cfe-commits cfe-commits at lists.llvm.org
Mon Aug 21 10:48:00 PDT 2023


Author: Felix
Date: 2023-08-21T17:47:14Z
New Revision: 4001ae175cbe351d496a6cd5481a554b346f706d

URL: https://github.com/llvm/llvm-project/commit/4001ae175cbe351d496a6cd5481a554b346f706d
DIFF: https://github.com/llvm/llvm-project/commit/4001ae175cbe351d496a6cd5481a554b346f706d.diff

LOG: [clang-tidy] readability-container-size-empty - detect missing usage of .empty() on string_literals

Detect comparison between string and empty string_literals.

Fixes #64547

Reviewed By: PiotrZSL

Differential Revision: https://reviews.llvm.org/D158346

Added: 
    

Modified: 
    clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.cpp
    clang-tools-extra/docs/ReleaseNotes.rst
    clang-tools-extra/test/clang-tidy/checkers/readability/container-size-empty.cpp

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.cpp b/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.cpp
index e24cb195e70cb5..0ef0389dcc99b9 100644
--- a/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.cpp
@@ -94,6 +94,14 @@ AST_MATCHER(QualType, isIntegralType) {
   return Node->isIntegralType(Finder->getASTContext());
 }
 
+AST_MATCHER_P(UserDefinedLiteral, hasLiteral,
+              clang::ast_matchers::internal::Matcher<Expr>, InnerMatcher) {
+  if (const Expr *CookedLiteral = Node.getCookedLiteral()) {
+    return InnerMatcher.matches(*CookedLiteral, Finder, Builder);
+  }
+  return false;
+}
+
 } // namespace ast_matchers
 namespace tidy::readability {
 
@@ -166,9 +174,11 @@ void ContainerSizeEmptyCheck::registerMatchers(MatchFinder *Finder) {
       this);
 
   // Comparison to empty string or empty constructor.
-  const auto WrongComparend = anyOf(
-      stringLiteral(hasSize(0)), cxxConstructExpr(isDefaultConstruction()),
-      cxxUnresolvedConstructExpr(argumentCountIs(0)));
+  const auto WrongComparend =
+      anyOf(stringLiteral(hasSize(0)),
+            userDefinedLiteral(hasLiteral(stringLiteral(hasSize(0)))),
+            cxxConstructExpr(isDefaultConstruction()),
+            cxxUnresolvedConstructExpr(argumentCountIs(0)));
   // Match the object being compared.
   const auto STLArg =
       anyOf(unaryOperator(

diff  --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 6b910920f6b7b6..470f06d82bf1d5 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -126,7 +126,7 @@ New checks
 - New :doc:`bugprone-incorrect-enable-if
   <clang-tidy/checks/bugprone/incorrect-enable-if>` check.
 
-  Detects incorrect usages of ``std::enable_if`` that don't name the nested 
+  Detects incorrect usages of ``std::enable_if`` that don't name the nested
   ``type`` type.
 
 - New :doc:`bugprone-multi-level-implicit-pointer-conversion
@@ -228,6 +228,10 @@ Changes in existing checks
   <clang-tidy/checks/performance/noexcept-swap>` check to enforce a stricter
   match with the swap function signature, eliminating false-positives.
 
+- Improved :doc:`readability-container-size-empty
+  <clang-tidy/checks/readability/container-size-empty>` check to
+  detect comparison between string and empty string literals.
+
 - Improved :doc:`readability-identifier-naming
   <clang-tidy/checks/readability/identifier-naming>` check to emit proper
   warnings when a type forward declaration precedes its definition.

diff  --git a/clang-tools-extra/test/clang-tidy/checkers/readability/container-size-empty.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/container-size-empty.cpp
index ae67bf2e92eb0d..592ffc21f41a4f 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/container-size-empty.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/container-size-empty.cpp
@@ -22,6 +22,10 @@ template <typename T> struct set {
 };
 }
 
+namespace string_literals{
+string operator""s(const char *, size_t);
+}
+
 }
 
 template <typename T>
@@ -461,7 +465,7 @@ int func(const std::vector<int> &C) {
 constexpr Lazy L;
 static_assert(!L.size(), "");
 // CHECK-MESSAGES: :[[@LINE-1]]:16: warning: the 'empty' method should be used
-// CHECK-MESSAGES: :90:18: note: method 'Lazy'::empty() defined here
+// CHECK-MESSAGES: :94:18: note: method 'Lazy'::empty() defined here
 // CHECK-FIXES: {{^}}static_assert(L.empty(), "");
 
 struct StructWithLazyNoexcept {
@@ -492,17 +496,17 @@ template <typename T> void f() {
   if (templated_container.size())
     ;
   // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}if (!templated_container.empty()){{$}}
   if (templated_container != TemplatedContainer<T>())
     ;
   // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}if (!templated_container.empty()){{$}}
   // CHECK-FIXES-NEXT: ;
   CHECKSIZE(templated_container);
   // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: CHECKSIZE(templated_container);
 }
 
@@ -575,74 +579,74 @@ bool neverInstantiatedTemplate() {
   if (templated_container.size())
     ;
   // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}if (!templated_container.empty()){{$}}
   if (templated_container != TemplatedContainer<T>())
     ;
   // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}if (!templated_container.empty()){{$}}
   // CHECK-FIXES-NEXT: ;
   while (templated_container.size())
     ;
   // CHECK-MESSAGES: :[[@LINE-2]]:10: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}while (!templated_container.empty()){{$}}
 
   do {
   }
   while (templated_container.size());
   // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}while (!templated_container.empty());
 
   for (; templated_container.size();)
     ;
   // CHECK-MESSAGES: :[[@LINE-2]]:10: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}for (; !templated_container.empty();){{$}}
 
   if (true && templated_container.size())
     ;
   // CHECK-MESSAGES: :[[@LINE-2]]:15: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}if (true && !templated_container.empty()){{$}}
 
   if (true || templated_container.size())
     ;
   // CHECK-MESSAGES: :[[@LINE-2]]:15: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}if (true || !templated_container.empty()){{$}}
 
   if (!templated_container.size())
     ;
   // CHECK-MESSAGES: :[[@LINE-2]]:8: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}if (templated_container.empty()){{$}}
 
   bool b1 = templated_container.size();
   // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}bool b1 = !templated_container.empty();
 
   bool b2(templated_container.size());
   // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}bool b2(!templated_container.empty());
 
   auto b3 = static_cast<bool>(templated_container.size());
   // CHECK-MESSAGES: :[[@LINE-1]]:31: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}auto b3 = static_cast<bool>(!templated_container.empty());
 
   auto b4 = (bool)templated_container.size();
   // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}auto b4 = (bool)!templated_container.empty();
 
   auto b5 = bool(templated_container.size());
   // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}auto b5 = bool(!templated_container.empty());
 
   takesBool(templated_container.size());
@@ -651,7 +655,7 @@ bool neverInstantiatedTemplate() {
 
   return templated_container.size();
   // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: the 'empty' method should be used
-  // CHECK-MESSAGES: :33:8: note: method 'TemplatedContainer'::empty() defined here
+  // CHECK-MESSAGES: :37:8: note: method 'TemplatedContainer'::empty() defined here
   // CHECK-FIXES: {{^  }}return !templated_container.empty();
 }
 
@@ -753,7 +757,7 @@ bool testArraySize(const Array& value) {
   return value.size() == 0U;
 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: the 'empty' method should be used to check for emptiness instead of 'size' [readability-container-size-empty]
 // CHECK-FIXES: {{^  }}return value.empty();{{$}}
-// CHECK-MESSAGES: :731:8: note: method 'array'::empty() defined here
+// CHECK-MESSAGES: :735:8: note: method 'array'::empty() defined here
 }
 
 bool testArrayCompareToEmpty(const Array& value) {
@@ -764,9 +768,23 @@ bool testDummyType(const DummyType& value) {
   return value == DummyType();
 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: the 'empty' method should be used to check for emptiness instead of comparing to an empty object [readability-container-size-empty]
 // CHECK-FIXES: {{^  }}return value.empty();{{$}}
-// CHECK-MESSAGES: :741:8: note: method 'DummyType'::empty() defined here
+// CHECK-MESSAGES: :745:8: note: method 'DummyType'::empty() defined here
 }
 
 bool testIgnoredDummyType(const IgnoredDummyType& value) {
   return value == IgnoredDummyType();
 }
+
+bool testStringLiterals(const std::string& s)
+{
+  using namespace std::string_literals;
+  return s == ""s;
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: the 'empty' method should be used
+  // CHECK-FIXES: {{^  }}return s.empty()
+}
+
+bool testNotEmptyStringLiterals(const std::string& s)
+{
+  using namespace std::string_literals;
+  return s == "foo"s;
+}


        


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